GMAT Sentence Correction (SC) | Re: Leaching, the recovery of copper from the drainage water of mines, as

Option A - Incorrect.

Remove the modifier in the middle - "the recovery of copper from the drainage of mines".

We get the sentence -

"Leaching , as a method of the extraction of minerals,it was well established ..." - Incorrect.

this is like saying "John, he went to the movies". the subject "leaching" is repeated again as "it". Hence, redundant.

Option B - Incorrect.
Remove the modifier in the middle - "the recovery of copper from the